Monthly Archives: March 2016

A new “best in class” seal for hydraulic cylinders with the ability to “thrive in unforgiving conditions” has been launched by Trelleborg Sealing Solutions.

The Zurcon® Glyd Ring® D has “leapfrogged” competitors thanks to its combination of performance and service life through optimized contact pressure and minimized heat generated from friction.

The innovative design incorporates two special grooves in the D-shaped profile of the seal to sustain an oil film for sufficient lubrication of the seal against its counter surface, ensuring adequate friction.

Extensive laboratory and field testing
The compact double-acting piston seal, which has been subjected to extensive laboratory testing and long term field testing in monitored applications, was developed in response to increasing demands from high-pressure hydraulic applications. Machines, equipment and motors are now being fitted with more powerful hydraulic cylinders, meaning the hydraulics are subject to higher pressures and temperatures.

The seal is manufactured from Zurcon® Z13 polyurethane (PU) material, which has been specially developed to cope with pressures of up to 500 bar/ 7,250 psi at both sides of the seal and at temperatures up to +120 °C / +248 °F. This gives the seal long life, even under demanding conditions. Offering superb mechanical and elastic properties, the seal loses none of its resilience over time and can be used in cylinders with lower quality inner walls.

Best-in-class for hydraulic cylinders
Andrew Longdon, UK Technical Manager at Trelleborg Sealing Solutions, said: “We have made subtle but significant changes to our previous Glyd Ring® compact double-acting piston seal, leading to a new and improved best-in-class seal for hydraulic cylinders with the ability to thrive in unforgiving conditions.

“In the latest more powerful hydraulic applications, high pressure is combined with elevated temperatures. Our new Zurcon® Z13 PU material used in Zurcon® Glyd Ring® D is specially developed to cope with this combination.

“We can now offer a seal for hydraulic cylinders that has a long life – this advanced solution has leapfrogged the competition.”

Global development
The pioneering seal was a joint development between Trelleborg’s research and development centre in Stuttgart, Germany, and their Polyurethane Centre of Excellence in Livorno, Italy.

The “convention defying” materials, known as Isolast® XploR™ J9523 perfluoroelastomer (FFKM) and XploR™ V9T82 fluoroelastomer (FKM), are engineered to maintain excellent sealing function at very low temperatures while subjected to high pressure conditions. The materials – which combine these characteristics with excellent chemical compatibility – have now met the ISO 23936 standard as well as revision three of NORSOK M-710.

Extreme low temperature sealing performance
Oil operators contending with extreme low temperatures, such as in the North Sea or around Canada and Alaska, will now have the opportunity to reduce operator costs without the need to use higher cost solutions and pre-heated equipment.

Low temperature sealing is becoming more common in oil and gas applications but standard Hydrogenated Nitrile Butadiene Rubber (HNBR) and FKM materials offer limited sealing capability below freezing when operated at high pressures. When an elastomer reaches its glass transition temperature (Tg) point, its properties change from being elastic and pliable to becoming solid and brittle. As a result, the elastomer is ineffective as a sealing solution and can be damaged easily.

RGD and sour service resistance
Isolast® XploR™ J9523 operating temperatures range from -40 °C to +240 °C / -40 °F to +464 °F with short excursions to 250 °C / +482 °F, while XploR™ V9T82 operates from -48°C to +200°C/-54°F to +392°F with short excursions to 210°C/+410°F. These low Tg values allow the materials to remain elastic under pressure at much lower temperatures than standard grades.

Andrew Longdon, UK Technical Manager at Trelleborg Sealing Solutions, said “Isolast® XploR™ J9523 and XploR™ V9T82 are both designed to stand up to rapid gas decompression (RGD), are suitable for sour service conditions and have an outstanding extreme low temperature performance.”

Pushing the barriers of science
“The ability of the materials to successfully function below -4 °F / -20 °C while under 15,000 psi / 100MPa is convention-defying and a further demonstration of Trelleborg’s constant determination to push the barriers of science and continue to provide more advanced and sophisticated sealing solutions.”

In addition to wellhead applications that may be subject to high operating pressures at low temperatures, Isolast® XploR™ J9523 and XploR™ V9T82 may also be ideal for drilling and intervention equipment that is stored in subzero conditions before being deployed into high pressure scenarios.